Insulated refrigerator casing



May 10, 1938. H. B. LINDSAY INSULATED REFRIGERATOR CASING Filed March l2, v1956 we/ag ffm ZJ Patented May 10, 1.9*38

' INSULAfrED nEr'mGEnA'ron casino.

Harvey B.

lindsay, chicago, n1., assignor romy- Zero Corporation, Chicago, Ill.,'a corporation of Delaware Application-March 12, 1936, serial N6.6s,s6v

The object of this invention is toautomatically dispose, without dripping, of the moisture that usually gathers on the bottorn of the insulation space of a refrigerator more particularly if it is insulated with substantially non-hygroscopic -or non-absorptive insulating material.

It has been proven that humidity in the air vfunctions as a-true-gas; that 'it is not minute 'droplets of water carried directionally by the air.

It is also known that this gas of H2O is nearly' twice as tenuous .as the air mixture and under the laws of gases nearly four times as penetra'. tive. Y

As it is impossible commercially to build the walls of a refrigerator, etc., so gas-tight that they would maintain -a vacuum successfully, it is obvious that it isimpossible to keep out this gas of.

` H2O-commonly called water vapor-which is nearly four times as penetrative as air.

It is a fact, and the above explains it, that Water gradually but inevitably forms in the in-4 sulation space of-a refrigerator orrefrigerator chamber under refrigeration, 'Ihis water-comes from the penetration ofwater vapor through the porositie's or cracks of the outside shell.this water vapor being under denite vapor pressure to penetrate to the cold side.

At rst this water vapor that is penetrating the outside shell, condenses on the outside surface of the inside liner of the refrigerator and in intimate contact with the usual so-called waterproof Wrapping supposed toprotect the insulation. As this wrapping becomes cold from its moist contact with the cold line'r, however, the condensation then begins to take vplace on the face of the wrapping next the insulating material and in intimate contact with the latter. Thereupon two forces are set up onthis water .of condensation: The forces of absorption,.mostly capillarity of the insulating material, and the surface repulsion of that material for water (as for example, that of wax).

If the surface repulsion exceeds the capillary forces, the insulatingmaterial Will remain dry indefinitely. But if the capillaryforces exceed the surface repulsion of the material it will gradually become damp, moist or wet. InV the first instance the insulation is referred to as non-hygroscopic, in the second, hygroscopic.

In the case of a refrigerator insulated with non-hygroscopic insulation, while the condensation described above will form on the outer surface of the liner, it will trickle down and eventually form a poolof water at the bottom of the refrigerator. If the wrapper becomes wet and (ci. 22o- 14) cold and condensation then -occurs between it and the non-hygroscopic insulant, the latter refuses to get moist and such condensation nds its way down the wrapper and-out of the joints of such insulant, andV so into the'bottomofthe refrigerator shell. vWhere vlined with hygroscopic insulating material, the condensation is absorbed in the -insulation to eventual saturation. 'I'his explains why refrigerators insulated with non-hygroscopic material' and in use for somev ltimewill often show water dripping or running downthe legs. AIf the bottom of the refrigerator is 'a water-tight pan-fastened tothe sides'and back,.then if lthe refrigerator is tilted the water runs out in considerable quantities. As stated, `this invention is for the purpose of disposing of the water sol forming in the bottom of a refrigerator, or substantially such, without any sign of drip or running down the legs. Iam aware that certain devices have been pro-- posed in the nature of air Valves designed in the hope that they would effect the expulsion of water vapor by'breathing, but such efforts have proved impractical for this purpose. The device Y of .the present invention, however, operates upon an entirely dierent principle, vas will presently appear. The invention may best be understood by reference to the accompanying drawing, in which Figi 1 is a vertical section of a refrigerator --chamber and lits insulating space through a me- -dian plane'between front and back, and including a moisture-disposal device constructed in accordance With-my invention.

Fig. 2 Yis a horizontal detail section taken on line 2-2 of Fig. 1.

Fig. 3 is a fragmentary vertical section showing a modied form of moisture-disposal device constructed in accordance with my invention.

Fig. 4 is a detail section showing a still further modification of the form of device shown in Fig. 3. Referring now to details of the embodiment of my invention illustrated in Figs. 1 and 2, the refrigerator casing is indicated generally at I0, and includes an outside shell I l, such as sheet steel or the like, an inner or inside lining I3, usually of porcelain enameled steel, and insulating-.material I2 of any suitable form between the outside shell II and inner liner I3. The insulating material l2 is preferably non-hygroscopic, although the inner wrapper or layer only of the insulating material adjacentthe inner lining I3 may be non-hygroscopic, if desired. As shown in Fig. 1, the four upper edges of the bottom slab of insu- .same,at-th`e bottom of the slab or package of in the middle ofl the latter; or, with the pan as' self-supporting absorptive material, such as the board forms of insulation known in the industry as Celotex, Insu1ite" or the like. 'Ihe sheet I6 is suitably supported against the bottom IIB as by cleats or channels II welded or soldered to said bottom wall.

In the modified form of the invention illustrated in Fig. 3, a separate pan I8 is supported above the bottom slab I2 of insulation, said pan being slightly dished toward a center aperture I9. 'Ihe edges oi' said pan extend slightly beyond the lateral sides of liner I3 so that water trickling down the sides of said liner will be caught by said pan. A suitable hole or channel 20 is formed in the bottom slab of insulation I2b beneath the aperture I9 and aiording communication to the discharge passage I4a in the bottom IIa of the shell II. An absorptive board I6 is secured beneath the passage I4a as in the form of device shown in Fig. 1.

In the form shown in Fig. 4, the arrangement is similar to that illustrated in Fig. 3, excepting that a tube 2l extends through hole 20 and con-` nects the aperture I9 of pan I8 with the discharge passage Il, as shown. 'I'his arrangement is preferable Where the bottom slab of insulation is partially or wholly hygroscopic.

In operation, moisture condensing on the top, sides and back of the liner and being refused by the adjacent non-hygroscopic insulation will trickle down the liner and either seep between the side insulation and the bottom insulation to the bottom of the shell and there trickle to the hole in Figs. 3 and 4, the moisture trickling down the liner will be caught in the pan, led to the hole 28 and thence to the discharge hole I4 in the bottom of the shell.'

On reaching this hole in the bottom of the shell, the water will be absorbed by the sheet of absorptive material I6, spreading laterally through said sheet considerably, and gradually towards the bottom surface, and on reaching that bottom surface will-evaporate to the surrounding air. Thus the hole Il is eectively sealed against passage of heat or ordinary air currents into the insulation space, and yet the water of condensation may escape through the sheet of absorptive material by dispersion and evaporation. Further, the minute channels through the material of the evaporator board being substantially filled with the water seeping from the escape hole to the evaporating surface, ingress of water vapor therethrough is reduced'to a negligible amount.

Experiment has shown that this is a constant operation. The evaporating sheet I5 can of course be covered with perforatedl metal or with Wire gauze, if desired, without interfering with its evaporating functions.

While the hole Il can be quite small and yet take care of all the moisture as it forms and reaches the hole, the evaporating surface of evaporator board I 6 must be sufficient to dispose by evaporation of all moisture reaching and soaking into the evaporator board. Experiment has shown that even under the `severest conditions obtaining in a kitchen and with a very faulty outside shell to the refrigerator (full of openings and seams) an evaporating area of 30 square inches is quite suilicient. Of course, the better the shell (the more it retards water vapor entry) and the better the conditions (the less humidity in the air )the less area of evaporating board is required under those conditions.

In those forms of refrigerating devices, for example an electric domestic refrigerator, where the machine is below the insulated food chamber the warm air from the condenser not only accelerates the desired evaporation from the evaporator board, but thev evaporation tends to cool the ambient air and so increase the efiiciency of the condenser. However, all that is required for the satisfactory operation of thisvinvention is reasonably free access of air to the evaporator ezboard.

Although I have illustratedand described certain embodiments of my invention, it will be understood that I do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of my invention as defined in the appended claims.

1. In a refrigerating device. an outer casing and an inner lining having insulation material therebetween, saidouter casing having a water discharge opening at the bottom thereof, and a sheet of absorptive material secured to said outer casing and covering said discharge opening.

2. In a refrigerating device, an outer casing and an inner lining having insulation material therebetween, said outer casing having a water discharge opening at the bottom thereof, and asheet of absorptive material secured to said outer casing and covering said discharge opening, but having its exterior surface evaporatively exposed to the surrounding air.

3. In a refrigerating device, an outer casing and an inner lining having insulation material therebetween, said outer casing having a water discharge opening at'the bottom thereof, means below said inner lining for directing water of condensation from the sides of said lining to said discharge opening, and a sheet of absorptive material secured to the bottom of' said casing and closing said discharge opening to the outer air.

HARVEY B. LINDSAY. 

